Abstract: Five planting modes of winter conservation tillage in paddy field, including potato with straw mulching under zerotillage(T1), ryegrass direct seeding under zerotillage (T2), rape direct seeding under zerotillage (T3), oat grass direct seeding under zerotillage（T4） and the control (CK), were designed to study the changes in the soil enzyme activities and their effects on leaf senescence of hybrid rice Guodao 6 during grain filling. Compared to the control (CK), T1, T2 and T3 treatments could significantly increase the soil proteinase, neutral phosphatase, catalase and invertase activities with the highest soil enzyme activity under T1 treatment. T1, T2 and T3 treatments could effectively delay the rice leaf senescence during grain filling. Further study showed that the degradation of chlorophyll and the decline of the soluble protein content were slowed down, and the superoxide dismutase and peroxidase activities were higher as well as the malondialdehyde content were lower under T1, T2 and T3 treatments than those in control (CK). Among the soil enzymes, soil proteinase had the largest influence on the rice leaf senescence, followed by catalase, neutral phosphatase and invertase. Rice leaf senescence index during the middlelate grain filling stage was significantly correlated with rice yield.

Key words: rice, conservation tillage, soil enzyme activity, leaf senescence, relationship

摘要： 为研究稻田冬季保护性耕作不同种植模式对土壤酶活性以及水稻成熟期叶片衰老的影响， 设计了5种种植模式：免耕直播稻草全程覆盖马铃薯（T1）、免耕直播黑麦草（T2）、免耕直播油菜（T3）、免耕直播燕麦草（T4）和空闲（CK），供试品种为杂交组合国稻6号。与对照（CK）相比,T1、T2和T3处理均可显著提高土壤蛋白酶、中性磷酸酶、过氧化氢酶以及转化酶活性，尤其是T1处理，其土壤酶活性明显高于其他处理，而T4处理与对照相比，差异不明显。T1、T2和T3处理均可有效延缓水稻成熟期剑叶的衰老，主要表现为成熟期剑叶中的超氧化物歧化酶、过氧化物酶活性、可溶性蛋白质和叶绿素含量下降缓慢，丙二醛含量上升的幅度较小，相对于对照（CK），差异均达显著水平。在本试验条件下，土壤酶对水稻叶片衰老的影响程度依次为蛋白酶>过氧化氢酶>中性磷酸酶>转化酶。叶片衰老对水稻产量的影响主要表现在灌浆中后期。

关键词: 水稻, 保护性耕作, 土壤酶活性, 叶片衰老